If you have ever wondered if punctuation is truly important, try reading a passage that does not have punctuation. It in nearly impossible to correctly figure out what the writer was trying to say. Punctuation tells us when one idea stops and another starts. It tells use who owns things and who said what. Punctuation helps us to understand what we are reading.
Capitalization is also important, generally we capitalize one of a kind things. We capitalize proper names like Bill and America because they refer to a particular person or place. We capitalize name brands like Band-Aid but not the product-bandages. We also capitalize nations, religions, places, languages, and unique items like the Declaration of Independence.
Abbreviations should only be used if necessary to refer to time, a person's title like Dr., or organizations that are usually referred to by their initials.